DENREES ATMOSPHERE CONTROL PROCEDURE AND SYSTEM

Abstract

The invention relates to a method for controlling the atmosphere of foodstuffs, in particular plant foodstuffs (1), in an enclosure (2), the method comprising steps of - preferably, monitoring a quantity of fermentation stress marker in or around at least one of the foodstuffs (1) over time, - (b, c, d) establishing in the enclosure, a stress inducer peak (P1), said stress inducer being correlated with said stress marker so that the peak (P1) induces an increase in the quantity of stress marker, and - (e) establishing in the enclosure, a stress inducer setpoint (C(02)) limiting the decrease in the quantity of stress marker, the setpoint (C(02)) being below, in particular above, said peak. The invention further relates to an automaton and an atmosphere control system.

Description

The present invention relates to a method for controlling the atmosphere, namely a method for controlling the preservation of foodstuffs in an enclosure. The objective of this type of method is to calibrate, in particular, the gases, the temperature, the pressure, around the foodstuffs, in particular plant foodstuffs, in order to improve their preservation and delay putrefaction as much as possible. The invention further relates to a computer program for implementing the method as well as an associated automaton and system. In the field of preserving fruits such as apples, maintaining a normal atmosphere of 21¾ oxygen leads to a short-term combustion of the plant's energy reserves, namely carbohydrates, by respiratory processes in the fruit. The total removal of oxygen leads to a metabolic reversal unfavorable to preservation, namely a transition from a respiratory process to a fermentation process. To overcome these disadvantages, controlled atmosphere systems have been proposed in which the amount of oxygen is maintained at 5¾. In general, controlled atmosphere systems inject nitrogen and purify the CO2 using known processes. One objective of the invention is to propose a method for better controlling the content of stress inducers such as oxygen, in order to improve the preservation of foodstuffs over time by limiting the loss of quality of the foodstuffs. To do this, the invention proposes a method for controlling the atmosphere of foodstuffs, in particular plant foodstuffs, in an enclosure, the method comprising steps of - preferably, monitoring a quantity of fermentation stress marker in or around at least one of the foodstuffs over time, - establishing in the enclosure, a peak of stress inducer, said stress inducer being correlated with said stress marker of so that the peak induces an increase in the amount of stress marker, and - establish in the enclosure, a stress inducer setpoint limiting the drop in the quantity of stress marker, the setpoint being different from said peak. In particular, in the case of apples, the reaction to oxygen deficiency stress prevents the molecule alpha-famesene from oxidizing. This molecule is found on the surface of the apple. When it oxidizes, it attacks the cell membrane of the upper layers of the fruit. In simple terms, this stress reaction prevents post-storage and highly destructive diseases such as various "scalds" or vitrescences. Advantageously, the peak and the stress inducer setpoint are chosen to annihilate the respiratory process and therefore limit the combustion of energy reserves and annihilate the oxidation of α-famesene, but without excessively engaging the fermentation process without, however, affecting the said organoleptic qualities of the apples at the end of storage. This results in longer storage of the foodstuffs, in particular fruits, in the enclosure. Maintaining a constant but low fermentation state makes it possible to maintain the quality of the foodstuffs because the energy reserves are consumed much less quickly in the case of fermentation than in the case of respiration. Furthermore, controlling the amount of stress marker allows the process to be adapted to precise conditions, in particular an accurate estimation of the fermentation or respiration process. According to other aspects taken individually or combined according to all technically feasible combinations: - the method further comprises steps of - identify at least one stress marker threshold or a time when this threshold is reached, and - establish in the enclosure, a new peak of stress inducer inducing an increase in the quantity of stress marker; and / or - the method further comprises steps of establishing in the enclosure, a new peak of stress inducer inducing an increase in the quantity of stress marker prior to an opening of said enclosure; and / or - the quantity of stress marker is measured in the foodstuffs by means of at least one probe preferably introduced into at least one of the foodstuffs; and / or - the intensity of the peak and preferably that of the setpoint, are adjustable by user j and / or - the stress marker is ethanol and the stress inducer is preferably dioxygen; and / or - the oxygen setpoint is less than 2¾, preferably less than 1%, more preferably 0.4¾; and / or - at least one of said dioxygen peaks is less than 1%, preferably less than 0.5¾, more preferably 0.2¾; and / or - at least one of said oxygen peaks is 0.1 to 0.3¾, preferably 0.2¾, below the oxygen setpoint; and / or - the threshold is greater than or equal to 90 ppm and less than or equal to 120 ppm, preferably around 110 ppm. The invention further relates to a computer program product comprising portions of software code readable on a control unit such as a computer, configured to give control instructions for carrying out the steps of the method according to the invention, when implemented by the control unit. Another object of the invention relates to an automatic device for controlling the atmosphere of foodstuffs, in particular vegetable foodstuffs, comprising a computer program product according to the invention. The invention further relates to a system for monitoring the atmosphere of foodstuffs, in particular plant foodstuffs, the system comprising - preferably an enclosure, - an automaton according to the invention, - at least one ethanol measuring probe. Alternatively, the invention may also relate to a method for controlling the atmosphere of foodstuffs, in particular plant foodstuffs, in an enclosure, the method comprising steps of - preferably, monitoring a quantity of stress marker in or around at least one of the foodstuffs over time, - establishing in the enclosure, a peak of stress inducer, said stress inducer being correlated with said stress marker so that the peak induces a drop in the quantity of stress marker, and - establish in the enclosure, a stress inducer setpoint limiting the increase in the quantity of stress marker, the setpoint being below, in particular below, said peak. The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures, in which: - figure 1 is a diagram of the method according to the invention; - Figure 2 is a diagram of the evolution from September 1 to March 31 of a stress inducer, in particular oxygen, and that of a marker of fermentation stress, in particular ethanol; and - Figure 3 is a diagram of an atmosphere control system according to the invention. The present invention relates to a method for controlling the atmosphere, in particular for the preservation of plant foodstuffs. 1, more particularly apples or pears. The method is particularly suitable for all varieties of apples and pears. The method is carried out in an enclosure 2 in which the plant foodstuffs 1 are stored. Enclosure 2 is in particular a refrigerated enclosure. The method according to the invention involves a stress marker which is preferably ethanol; and a stress inducer correlated with the stress marker. The stress inducer is preferably dioxygen. The stress here is the annihilation of a respiratory process and the initiation of a light fermentation process. Another stress marker can be considered in this configuration, such as, in particular, lactate or ethylene and another stress inducer such as, in particular, carbon dioxide. Lactate has the advantage of being soluble and more easily measurable. An ethylene measurement can be added as a supplement to the control, in fact ethylene is a hormone-like molecule released by the apple during its respiration and ripening process, prevailing in the refrigeration chamber. Depending on the stress marker and the stress inducer monitored, the evolution of their quantity can be in the same direction or in an opposite direction to those of ethanol and dioxygen without departing from the scope of the invention. In the case of an opposite evolution, the values ​​are reversed in the same principle, for example the peaks are reversed. The control of parameters other than oxygen, such as other gases, temperature, pressure, humidity around the food can be done according to known processes. For example, these parameters are: - CO2 î 1% (g / g)} - Temperature:...0.8 C; - Pressure:...0 mbar; - Humidity: ...9 6%. In the preferred variant, the H2 content is set at 3%. Nitrogen is preferably the gas used to expel oxygen and lower the oxygen content of the enclosure. Another parameter lowering the oxygen content is the respiration of the food, which will allow in particular to consume all the oxygen contained in the refrigerated enclosure until reaching 0%, in order to reach the stress peak. Enclosure 2 is put into operation, for example following a step (a). As soon as the foodstuffs are placed in enclosure 2, the quantity of oxygen in enclosure 2 is lowered. In particular, a peak of oxygen Pi is established below the conventional content for the preservation of foodstuffs, for example at a value less than 1%, preferably less than 0.5%, more preferably 0.2% (by volume). These values ​​induce good results for plant foodstuffs, in particular apples. The values ​​of Px depend on several parameters such as the state of the apple at picking, its advanced or early state of maturity, the climatology, the terroir, the state of the orchards, etc. Thus, the conservation thresholds relating to stress peaks depend on these parameters and also on the variety, in particular apple or pear. Indeed, different varieties of apple do not have the same reaction and conservation parameters.The same goes for pears. Advantageously, the oxygen peak allows the respiratory process to be quickly and intensely annihilated and the consumption of carbohydrate reserves to be limited, while slightly engaging the fermentation process. For example, the peak is established by applying a dioxygen setpoint C{02) at 0% until the dioxygen content reaches the desired value. This first setpoint at 0% can be established in a second step (b). The decrease in the dioxygen content can be identified by a step (c). The peak of dioxygen Px reached can be identified by a step (d). Alternatively, a quantity of stress marker, in particular ethanol, may be monitored in or around at least one of the foodstuffs over time. Advantageously, monitoring, preferably continuously, the quantity of ethanol makes it possible to verify whether the plant foods are in a respiratory or fermentation process, and to what extent they are engaged in this process. In addition, this monitoring makes it possible to check the effectiveness of the oxygen peak for the foods considered in the particular situation, and to check whether the amount of oxygen needs to be further reduced. Oxygen monitoring, which makes it possible to use a set point of 0¾ and to check whether the oxygen peak Pi is reached. Since oxygen is correlated with ethanol, verification of the oxygen content can be done by monitoring only the ethanol content, for example by weight, to check whether an ethanol peak P2 is reached. Preferably, the ethanol peak P2 is greater than or equal to 100 ppm and less than or equal to 140 ppm, more preferably about 120 ppm. As can be seen in Figure 2, the operator can raise the, more specifically program the rise of the, O2 level slightly before the ethanol reaches 120 ppm. Indeed, the fermentation process has a certain inertia that can be anticipated, namely the rca, called regulation by anticipated control, to not raise too high in ethanol and exceed the planned measurements. This avoids having additional stress. Thus, when the ethanol level begins to rise, the operator can preferably raise, more specifically program the rise of, the O2 setpoint, even if it means reaching the peak ethanol rise in 2 phases, an algorithm is preferably provided to automate this operation while limiting the risks. In other words, when the measured percentage oxygen value reaches the peak Pi, the ethanol content begins to rise, for example, the Pi value is 0.2%. Simultaneously, P2 has risen by a few ppm of ethanol depending on conditions related to the specific food being stored. It is determined whether the P2 value is sufficient, for example at 120 ppm. The oxygen level is then adjusted, in particular by introducing it into the cold room, to stabilize this ethanol level. A P2 ethanol peak of a few ppm indicates the end of the respiratory process for apples, without the apples being too involved in a respiration process. Maintaining a constant but low fermentation state helps maintain the quality of the apples because energy reserves are consumed very slowly in the case of fermentation, especially since an ethanol resulting in a few ppm, for example 120 ppm, denotes almost insignificant fermentation. As with Pj, the P2 value varies depending on the food, particularly depending on the apple or pear variety. This value can reach 500 ppm for the apple variety called "red" for example. The method then comprises a step comprising establishing a dioxygen C(O2) setpoint above the peak value. This step may be referred to as step (e). The atmosphere is maintained at this dioxygen C(O2) setpoint. Advantageously, the dioxygen setpoint makes it possible to limit the drop in ethanol and thus temporarily maintain the fermentation process while preventing the fruit from completely entering the fermentation process. For example, the dioxygen C(O2) setpoint is less than 2%, preferably less than 1%, more preferably approximately 0.4% (by volume). A setpoint of 0.4% allows for better preservation of the apples and a taste maintained over time for several months. The C(O2) setpoint may also be greater than 2% depending on the foodstuff, in particular the apple or pear variety. In particular, the oxygen peak Pi is at a value lower than that of the C(o3> setpoint, for example for a given plant product. We can consider a plant product which would have a C(o2) setpoint different from that of apples, in which case, the peak may have a different value. Preferably, the oxygen peak Pi is 0.1 to 0.3%, preferably 0.2%, below the oxygen setpoint. More generally, the CO2 maintenance range, depending on the variety, is between 0.5¾ and 3¾. A calibration can be carried out for a given variety using test methods. In the case where another stress inducer and / or another stress marker is used, the variations may be in the same direction or in an opposite direction to those of oxygen and ethanol. For example, one can consider a stress inducer whose quantity must be increased to induce stress, and / or a stress marker that decreases during stress. 10 Despite the CW3 oxygen instruction) limiting the drop of ethanol, it turns out that the amount of ethanol decreases slowly over time, which indicates that plant foods are gradually returning to a respiratory process. Monitoring the amount of stress marker can be used to identify at least one stress marker threshold Si below which the foodstuffs can be considered to be no longer sufficiently engaged in their fermentation process or to be returning to a respiratory process. In particular, the threshold Si is lower than the ethanol peak P2. For example, the threshold Si is greater than or equal to 90 ppm and less than or equal to 120 ppm, preferably about 110 ppm. The threshold Si reached can be identified in a step (f). Once this threshold Si has been determined and reached, a new peak of stress inducer can then be established in enclosure 2, inducing an increase in the quantity of stress marker. In particular, a dioxygen peak lower than the previous setpoint is established in enclosure 2. The new peak can be established by resetting an oxygen setpoint to 0¾, therefore in particular by returning to step (b), and so on. Alternatively, one can consider identifying a time when this threshold Si is reached, for example on average, and then establishing at this point the new peak of dioxide. The new peak can be the same, i.e., of the same value, as the previous Pi Peak or it can be different. Preferably, the same peak is used—for simplicity. After the new peak, a new C(02) oxygen setpoint is applied* This setpoint is preferably the same as the previous one(s) for simplicity, but it can be considered different. Furthermore, it is possible that enclosure 2 may be opened by an operator, for example to carry out measurements or checks. This opening of enclosure 2 leads to a sharp increase in the oxygen content in enclosure 2 and is detrimental to the preservation of the food because it would enter into a respiratory process, particularly if the last peak of oxygen occurred several days before opening so that the quantity of ethanol is slightly above the threshold. To avoid this drawback, the method may comprise a step of establishing in the enclosure 2, a new peak of stress inducer inducing an increase in the quantity of stress marker prior to an opening of said enclosure 2. More particularly, a new peak of dioxygen Pi is applied before the opening of the enclosure 2. Preferably, this new peak is applied approximately 24 h before the opening of the enclosure 2. The opening prediction step (PO), for example in 24 h, may be identified as a step (g). The peak Pi may be applied following steps (h) and (i) similar to steps (b) and (c), respectively. Depending on the time before opening, there may be a step (j) of peak Pi reached and (k) of setpoint C(02) which may be 0.4¾ before the opening (O.) of the enclosure 2, for example in a step (1). The new peak may also be different from the previous peak Pi in value. If speaker 2 is no longer in use, it can be switched off in step (m). Preferably, the amount of stress marker is measured in the foodstuffs by means of at least one probe 3 preferably introduced into the foodstuffs. Thus, the enclosure 2 is associated with this probe 3 for the implementation of the invention. In particular, the probe 3 is introduced into the flesh of the plant foodstuffs 1 so as to ensure the quantity of stress marker locally. 5 Advantageously, a probe in the food greatly increases the efficiency of the process because the probe is placed as close as possible to the flesh, namely near the place where ethanol is produced in liquid form. Probe 3 can be an adaptation of a so-called ElecFET sensor developed by the CNRS. 10 Preferably, several probes 3 are used, for example two to four or more probes 3. This makes it possible to monitor different harvest batches and to take into account the most sensitive reactions. The probe '3 can be coupled to a very high precision analyzer 4 which can be in the enclosure 2 or outside the enclosure 2. The measurement information of probe 3 is preferably visible to operators. An analyzer 4 can also be coupled to several probes 3. We can consider a probe for measuring lactate, ethylene 20 or another parameter correlated or not to the quantity of ethanol or to the respiratory or fermentation process. According to a variant, alternatively or preferably in addition to the probe 3 introduced into the foodstuffs, a contact probe (not shown) can be used in particular 25 to have confirmation of the measurements. This contact probe is in contact with the foodstuff, in particular the apple or the pear. According to a variant, the intensity of the peak Pi and preferably that of the setpoint C{02), are adjustable by a user. 30 Thus, a user can adjust these parameters to adapt them to a particular situation and / or to particular foodstuffs, in particular the species of apple or a plant product different from the apples. Another subject of the invention relates to a computer program product particularly suitable for the implementation, preferably automatic, of the method as described above. The computer program product comprises portions of software code readable on a control unit 5 such as a computer. The computer program product is configured to give control instructions for carrying out the steps of said method, when implemented by the control unit 5. For example, the program product is atmosphere control software loadable into said control unit. The program product can operate with stress marker quantity measurement data and, for example, control sources 6 or regulators in particular of gas, to apply the oxygen setpoint C(02) and / or the stress inducer peak Pi. The invention further relates to an automaton for controlling the atmosphere of foodstuffs, in particular vegetable foodstuffs, comprising a computer program product as described above. In particular, the automaton ccaitakes the control unit 5 and applies the control instructions. The invention further relates to a system for controlling the atmosphere of foodstuffs, in particular plant foodstuffs. The system comprises an enclosure 2, in particular a refrigerated enclosure, an automaton as described above, and an ethanol measuring probe 3. The method, the program, the automaton and the system according to the invention can each be added in addition to other usual systems as data confirmation or additional security. Indeed, this allows users to ensure that their usual system does not suffocate the apples by using for example the probe 3 and the automaton according to the invention. Index of references 1 s Vegetable products; 2 days pregnant; 3: Probe; 4: Analyzer; S r Control unit? 6 d Source in particular of gas; 5 a: Operation; b and h: Dioxygen (C(O2)) setpoint at 0%; c and i * decrease in O2 content j d and j: Oxygen peak (PI) reached, then ethanol peak (EtOH) reached; 10 e and ks Dioxygen (C(O2)) setpoint at 0.4%; f: SI threshold of ethanol reached t g î Opening forecast; 1 ; opening > m: extinction. 15

Claims

CLAIMS 1. Method for controlling the atmosphere of foodstuffs, in particular plant foodstuffs (1), in an enclosure (2), the method consisting of monitoring over time, in particular during the following steps, a quantity of a fermentation stress marker, in particular ethanol, in at least one of the foodstuffs by means of a probe introduced into at least one foodstuff, in relation to a defined peak (P2), to annihilate the respiratory process without excessively engaging the fermentation process, and comprising the following steps as soon as the foodstuffs are placed in the enclosure (2): lowering the amount of oxygen in the enclosure (2), establishing a peak oxygen (PI) below the conventional content for preserving foodstuffs at a value below 1%, preferably below 0.5%, more preferably 0.2% by volume, the oxygen as a stress inducer being correlated with said stress marker so that the peak PI induces an increase in the amount of stress marker; identify the drop in oxygen; identify that the peak oxygen (PI) setpoint has been reached; establishing a dioxygen setpoint value (C(O2>) in the enclosure (2) above the peak setpoint value (PI), the atmosphere being maintained at this dioxygen setpoint (C(O2)); identify at least one threshold (Si), lower than the peak (P2) of the stress marker below which the foodstuffs are no longer sufficiently engaged in their fermentation process and identify the reaching of this threshold (SI) to establish in the enclosure (2à) a new stress peak. 2 2. Method according to the preceding claim, further comprising steps of establishing in the enclosure, a new inductor peak. stress (Pi) inducing an increase in the quantity of stress marker prior to opening said enclosure (2). 4 3. Method according to one of the preceding claims, in which the intensity of the peak (Pi) and preferably that of the setpoint (C(o2>), are adjustable by a user.

4. Method according to one of the preceding claims, in which the stress marker is ethanol.

5. Method according to the preceding claim, in which the oxygen (C(o2)) setpoint is less than 2%, preferably less than 1%, more preferably 0.4%.

6. Method according to one of the preceding claims, in which at least one of said dioxygen peaks (Pi) is less than 1%, preferably less than 0.5%, more preferably 0.2%.

7. Method according to one of the preceding claims, in which at least one of said dioxygen peaks (Pi) is 0.1 to 0.3%, preferably 0.2%, below the dioxygen setpoint (C (02)) • 8. Method according to one of the preceding claims, in which the threshold (Si) is greater than or equal to 90 ppm and less than or equal to 120 ppm, preferably approximately 110 ppm.

9. Method according to one of the preceding claims, in which a contact probe is used in contact with the foodstuff to have confirmation of the measurements.

10. Computer program product comprising portions of program code recorded on a medium readable by a control unit (5) such as a computer, for implementing the steps of the method according to one of the preceding claims, when said program operates on the control unit (5).

11. Automated atmosphere control system for foodstuffs, in particular vegetable foodstuffs, comprising a program product computer according to the preceding claim.

12. System for controlling the atmosphere of foodstuffs, in particular 5 plant foodstuffs, the system comprising - preferably a speaker, - an automaton according to the preceding claim, - at least one ethanol measuring probe (3) designed to be introduced into a foodstuff.

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